Formula 1 drivers have been prohibited from stopping in the fast-lane of the pit-lane from this weekend's Sao Paulo Grand Prix in a clampdown by race director Niels Wittich.
In an attempt to avoid high-closing speeds during qualifying with cars backing up into the final corner, the FIA introduced a new system at the Italian Grand Prix of a minimum lap-time delta between the two Safety Car lines.
The time, decided after Friday practice, means drivers must not go any slower than the prescribed time or risk incurring a penalty, although no driver has been found guilty as those called to the stewards for a breach have been able to prove they did not meet the time as they went slower to allow a faster car through and not impede the driver.
Drivers have since 'gamed' the system by instead stopping in the fast-lane while exiting the pits to create the gaps of free air they need to prepare the car for a flying lap.
In Mexico, George Russell, Max Verstappen and Fernando Alonso were all called for alleged breaches, with the FIA's race director now stepping in with fresh guidance, starting from the Interlagos weekend.
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FIA race director in new rules clampdown
Wittich's new rules now expressly forbid drivers from stopping in the fast-lane of the pit-lane, which would be deemed as driving in an "unnecessarily slow" manner.
"As per Article 33.4 of the Formula 1 Sporting Regulations, drivers are not allowed to go unnecessarily slow, that includes stopping a car in the fast lane of the pitlane," Wittich wrote in his standard pre-event notes issued to every team.
"During the [Sprint] Shootout and Qualifying, drivers may create a gap between the pit exit lights and the SC2 line.
"Any driver who wishes to do so must drive as far to the left as possible to allow other drivers to pass them on the right side of the pit exit road."